GL_EXT_422_pixels
https://www.khronos.org/registry/OpenGL/extensions/EXT/EXT_422_pixels.txt
GL_EXT_422_pixels

	GL_422_EXT 0x80CC
	GL_422_REV_EXT 0x80CD
	GL_422_AVERAGE_EXT 0x80CE
	GL_422_REV_AVERAGE_EXT 0x80CF